Hi Linus, Very sorry that I had not responded quickly. When I was digging into tool version dependency, as you pointed out, gperf is a problem (but seemed one time breakage for gperf 3.1) flex seemed very stable for a long time. bison seemed a bit problem if old version is used. But, I did not have enough time to take a closer look. I thought I should respond after I tested more, but I has been pressed by my daily tasks, then time passed... Very sorry. Today, I just noticed gperf usage got dropped from the kernel. If CONFIG_MODVERSIONS is enabled, I notice lots of error messages. WARNING: EXPORT symbol "finish_open" [vmlinux] version generation failed, symbol will not be So, I think something was broken in scripts/genksyms/. Of course, it was a trivial conversion, so it should not be hard to fix... > gperf is clearly written by clowns that don't understand about > compatibility issues - it would have been trivial for them to add some > kind of marker define so that you could test for this directly rather > than depend on some kind of autoconf "try to build and see if it > fails" crap. One idea may be to process the output of "gperf -v" and embed GPERF_VERSION into the output .c files. But, if you are unhappy with gperf breakage this time, we can live without gperf. > It's likely not even any slower, but who the hell knows.. Do we even > care? It's almost certainly faster if you compare to generating that > gperf code. > For scripts/kconfig/, I think we do not care at all because we usually invoke it just once when we configure the build setting. If we enable CONFIG_MODVERSIONS, scripts/genksyms/ is invoked over and over again. Sorry, I have not evaluated if the perfect hash gives us noticeable advantage or not.. -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
